Does T-Mobile’s new ‘truly’ unlimited data plan signal an iPhone 5?

T-Mobile still doesn’t have an iPhone. Could a new policy, announced Wednesday, signal an iPhone 5 coming to the network?

It might, or it might not, but it means that the nation’s No. 3 and No. 4 wireless carriers have something that No. 1 and No. 2 do not: unlimited – and unthrottled – data. Currently, only Sprint and, as of Sept. 5, T-Mobile have such service.

In fact, recent moves by Verizon and AT&T toward shared deta plans, along with policies that encourage folks to move to those plans, could be the major reason behind T-Mobile’s shift. On the other hand, a move because an iPhone 5 is coming is not out of the question.

T-Mobile is the only one of America’s Big Four wireless carriers sans iPhone. In what has to grate on T-Mobile’s nerves, Apple has allowed some regional carriers access to the world’s best-selling single smartphone, but still has not gifted T-Mobile with the device.

Currently, although T-Mobile advertises unlimited data, once a customer passes a “cap,” the data speed is throttled to the point that it’s nearly unusable.

The new “truly” unlimited data plan costs $30 a month when bundled with a voice and text plan, for a total of $79.99 or $89.99 depending on it a customer wants wants 500 voice minutes or an unlimited voice plan.

Those who fit under T-Mobile’s “value” no-contract option will pay $20, for a total of $59.99 or $69.99, with the same restrictions as above.

The big negative to all this: the new plan cannot be combined with the Smartphone Mobile Hotspot feature, so customers who require that feature will be forced to continue with the current 5GB and 10GB rate plan options.

The T-Mobile plan will be available to both new and existing customers. This isn’t a promotion, but rather a permanent option, T-Mobile said.